Recent medical advances have allowed more patients to survive serious injuries or disease processes than ever before. Unfortunately, the period of bed rest required for recovery may lead to severe deterioration of muscle strength and the inability to support full body weight in standing. It is challenging for rehabilitation specialists to help these patients regain the ability to stand and begin ambulation. The challenge is especially great for obese patients. A common technique in current practice is to summon as many colleagues as practical to lift and maneuver the weakened patient to a standing position while he or she attempts to bear full weight through the lower extremities. This technique is not only dangerous, because of the risk of a fall, but it is also psychologically degrading for the patient as the activity reinforces the patient's dependence on others.
An alternative to mobilizing deconditioned patients with manpower is to use a tilt table. A tilt table resembles a stretcher having a top section that can be tilted gradually from a horizontal to a vertical position. The patient is transferred laterally from the hospital bed to the tilt table surface and secured to the table with straps placed across the knees and waist. The table's surface is then tilted to the desired inclination. A footboard at the lower end prevents the patient from sliding off the table and allows graded weight-bearing through the legs. The benefits of tilt table standing include a gradual retraining of the cardiovascular system to the demands of the body's upright position and the re-education of the balance mechanisms affected by long periods of bed rest.
Unfortunately, tilt tables have a significant limitation. The tilt table is only able to bring the patient to an upright position while simultaneously restricting movement of the lower extremities. This restriction prevents movement through the range-of-motion of the knee joints and greatly limits strengthening of the lower extremity musculature, because the legs are strapped to the table. The conventional tilt table design has no mechanism to enable a patient to perform lower or upper extremity exercise for strengthening or conditioning.
Exercise machines with a movable sled on inclined rails, which the user moves against the resistance of his body weight, are well known. Such devices are described in U.S. Pat. No. 4,383,684 of Schliep, U.S. Pat. No. 5,169,363 of Campanaro, U.S. Pat. No. 5,263,913 of Boren and U.S. Pat. No. 5,938,571 of Stevens. These pieces of equipment permit a user to exercise by using his legs or arms to move a moveable sled on which his body is supported on an inclined platform or set of rails. The inclination of the platform or rails on which the sled is moved may be changed to vary the resistance offered by the user's body weight. Such devices are designed for healthy users who are able access the apparatus from a standing position. In fact, the user must get on and off these devices in order to change the inclination or resistance level of the exercise device. Furthermore, these devices are made for simultaneous bilateral lower extremity exercise and may not be suitable for use by users that are unable to stand due to weakness or by users with one lower extremity that is non-weight bearing, such as a fractured or amputated leg.
U.S. Pat. No. 5,885,197 of Barton discloses an exercise apparatus with a stationary base on which is mounted a pivoting frame having a movable sled thereon. The apparatus includes a motor-drive for changing the angle of inclination of the pivoting frame. Although users are able to remain on the apparatus while the incline is changed, it is not safe for patients with severe deconditioning. Furthermore, there is no means of locking the sled in place while a user mounts the machine and no means of adjusting the sled travel. If a patient's knees were to buckle, the sled would slide down the rails and could injure the patient. In addition, a patient with severe weakness would be unable to keep his feet on the platform, as there is no means of supporting the legs or securing the feet to the platform. The carriage of the Barton patent, like that of the Boren patent, includes shoulder rests to allow a user to push the carriage up the inclined frame with his legs. These shoulder rests would prevent a lateral transfer of a user to the sled from a patient's bed. The only way to mount the device would be to sit on the carriage and slowly lower down between the rests. The Barton device also includes hand grips mounted on the guide rails for upper extremity workouts. However, since these grips are fixed in place, they would prevent a lateral transfer of a user onto the apparatus from a patient's bed.
Traction tables, in which a force is applied to effect spinal traction, are also well known. U.S. Pat. No. 3,741,200 of Morin describes a tilting table with multiple sections that can be locked and released so as to move with respect to each other on the table frame. By locking some sections together and permitting this joined subassembly to slide on the frame with respect to other sections, spinal traction may be produced on a patient on the table by the action of gravity. A traction device which does not include a tilting feature is described in U.S. Pat. No. 5,024,214 of Hayes. Inversion tables, which invert to produce spinal traction, are described in U.S. Pat. No. 4,867,143 of Morin, U.S. Pat. No. 5,551,937 of Kwo and U.S. Pat. No. 5,967,956 of Teeter. Motorized versions of the traction table are described in U.S. Pat. No. 4,113,250 of Davis and U.S. Pat. No. 4,672,697 of Schürch. These tables are designed to treat back and neck ailments by inverting a patient who is secured to a platform to a head-down position. Such tables would not be used for the treatment of muscular weakness and would be unsafe to use on the population of patients with severe deconditioning. Tilting such patients to a head-down position could lead to respiratory distress, increased blood pressure and increased intracranial pressure, all of which are potentially harmful to the patients.
Lastly, with exception of the traditional tilt table, all of the other devices described above are not designed for easy transportability, especially for movement into and out of hospital rooms and intensive care units. It would be desirable if a table was mobile to allow transport to hospital rooms and could function as a tilt table and an exercise apparatus. It would also be desirable for the table to accommodate patients with a non-weight bearing restriction such as a fractured or amputated leg and for the head of the patient supporting carriage to elevate allowing improved respiration for patients.